The parents of a five-year-old girl knocked down by a hit-and-run driver today spoke of their heartbreaking wait to see if she will pull through.

The next 24 hours are vital for critically ill Oonagh O'Reilly, from Monagh Drive in west Belfast, who was left lying by the roadside after being hit by a blue van on Norglen Road, in the Turf Lodge area yesterday afternoon.

Oonagh, who celebrated her fifth birthday last month, was taken to the Royal Victoria Hospital where she is suffering from head injuries, shattered ribs, pierced lungs and blood in her liver.

Her parents, Stephen and Veronica O'Reilly, say they are currently living through "every parents' worst nightmare".

They are anxiously waiting the results of tests to see if their daughter is suffering from brain damage.

They have also been told that doctors are also concerned about blood in her liver.

Her father Stephen said he felt utterly distraught when he saw his little daughter lying by the roadside.

"It is unbelievable the damage that has been done to her.

"She is only a tiny thing and she must have been hit very hard.

"We have been told that the next 24 to 40 hours are critical and we are just nervously waiting to hear if she is going to pull through.

"We did not sleep at all last night just thinking of her lying there in hospital. At the minute I'm just more concerned about Oonagh getting better than finding out who did this," he said.

According to Oonagh's mother, Veronica, where the accident happened is a very busy road and there are a lot of road works being carried out at the moment.

She said: "I have nothing against who did this. I just want Oonagh better. I'm sure whoever did this feels terrible about what he has done.

"What I do not understand is, that for such a busy road, nobody saw the accident.

"How is that possible?"

Oonagh is a pupil at the nearby Irish school, Gaelscoil na Mona.

She had just arrived home from school and left to go out and play with her seven-year-old friend when the accident happened around 2.40pm.

Her friend wasn't hurt.

A special Mass was held this morning for Oonagh, her parents, three sisters and two brothers, at Holy Trinity church by parish priest Father Matthew Wallace.

Fr Wallace, who is a friend of the family, last saw Oonagh at a family Christening on Sunday.

"Everyone's thoughts and prayers are with the family at this very sad time," he said.

Police are continuing their enquiries into the incident and are currently asking anyone who may have spotted a blue van, possibly with frontal damage, to come forward.

A spokesman for the PSNI said: "We need the community's help in investigating how this collision, which has left a five- year-old girl seriously ill in hospital, occurred.

"We would ask anyone who either witnessed this serious road traffic incident on Norglen Road, or who may have seen a blue van acting suspiciously after the collision occurred, to contact police at Woodburn."